Solution to Activity 2.3 of NCERT Class 9 Science Chapter 2 Is Matter Around Us Pure?

3. Complete Activity 2.3 (Page 16).

• Take approximately 50 mL of water each in two separate beakers.

• Add salt in one beaker and sugar or barium chloride in the second beaker with continuous stirring. • When no more solute can be dissolved, heat the contents of the beaker to raise the temperature by about 5^oC.

• Start adding the solute again.

Is the amount of salt and sugar or barium chloride, that can be dissolved in water at a given temperature, the same?

Answer:

Aim: To determine which dissolves more, salt or sugar, and observe what happens when the solution is heated and solute is added and conclude based on that.

Materials Required: Two beaker, water, salt, sugar, two burners,

Procedure:

(i) Take approximately 50 mL of water each in two separate beakers.

(ii) Add salt in the first beaker with continuous stirring.

(iii) Add sugar in the second beaker with continuous stirring.

(iv) When no more sugar and salt can be dissolved, heat the contents of the beaker to raise the temperature by about 5^oC. The start adding sugar and salt in the respective beakers. Note the observations.

Observations:

• A lot more sugar dissolves than salt.
• When the solution is heated to raise the temperature by about 5^oC, more solute can be dissolved.

Conclusions:

• Different substances in a given solvent have different solubilities at the same temperature.
• If temperature of the solution is increased, then the solubility of a substance increases.

“Activity 2.3 (Page 16).

• Take approximately 50 mL of water each in two separate beakers.

• Add salt in one beaker and sugar or barium chloride in the second beaker with continuous stirring. • When no more solute can be dissolved, heat the contents of the beaker to raise the temperature by about 5^oC.

• Start adding the solute again.

Is the amount of salt and sugar or barium chloride, that can be dissolved in water at a given temperature, the same?” – Solved.

Solutions to Group Activity
Solution to Activity 2.1
Solution to Activity 2.2
Solution to Activity 2.4
Solutions to Chapter 2 Is Matter Around Us Pure?